Fourteen accessions of African rice (
Oryza glaberrima Steud.) were tested for their responses to complete submergence. In most accessions tested, submergence promoted shoot elongation and the survival rates after transfer to air were low. However, there were two accessions with relatively high survival rates (> 70%): one (C0025) induced shoot elongation by flooding and the other (C8567) not. The response of C8567 was similar to that of the
O. sativa cultivar carrying the submergence-tolerance gene,
SUB1A-1, but C8567 did not possess the gene. This suggests that the submergence tolerance of
O. glaberrima should be elicited through a different mechanism from that of the tolerant
O. sativa cultivar. An accession (C8834) carrying
SUB1A-1 was found, which did not show submergence resistance with no expression of the gene. On the basis of morphological traits and DNA analysis of an
O. glaberrima-specific gene, the possibility arises that C8834 may belong to
O. sativa rather than
O. glaberrima.
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